Disco 2 Electrical problems and dead. crossed B fault code

Paul_Disco_II · Sep 18, 2020

Hello, I appreciate that I am new here, but any help would be greatly appreciated.
My 2001 TD5 Disco has been off the road for around 4 years, stood outside. When it was first parked up it started fine and had a full MOT.
Tried to get it started again but a significant part of the electrics isn't working. Key in ignition and turn it - all of the warning lights come on and then gradually go out except oil light, battery and the S&M lights flashing. There are six bongs and the gear indicator is flashing with what looks like a D with a line through it. Immobiliser light is blinking all the time.
The following are working: radio, heater, windscreen wipers, horn, screen wash, electric mirrors but everything else is dead.
So far, I have fitted a new battery (a good one recommended in another thread on here), key fob is working, cleaned out ECU red plug, checked fuses in the engine bay, cleaned the three earth fittings next to it - but I will be working through other earth connections.
I know that the damp has got in over the years through the sun-roof and so I think it might be a dodgy earth lead somewhere?
If anyone can help, it would be much appreciated. many thanks.

sierrafery · Sep 18, 2020

Hi. In your case the first suspect is the interior fusebox which might have water ingress, plenty of info on the forum, see this Please Help - No Crank No Start

Paul_Disco_II · Sep 18, 2020

Thanks Sierrafery - i'll have a look.

Paul_Disco_II · Sep 18, 2020

Got the internal fuse box out thanks to a very good video on youtube. Signs of water damage on the outside. I took it apart and there was evidence of water damage inside. Tried to clean it up and then refitted it but it didn't make any difference. I will get a second hand one off Ebay.
Having ready several threads on here, the warning on the dash is a crossed B.

sierrafery · Sep 18, 2020

Buy a fusebox removed from pre-facelift vehicle no matter what year that's important cos facelift fusebox will not work well and follow the replacement procedure which i revealed in that other thread

ronsealdeath · Sep 19, 2020

Fix the leak first or you will ruin the new one! Youve got to stop water getting in on a D2, it just causes too much havoc over time

Paul_Disco_II · Sep 21, 2020

Hi, thanks - that is a very good point. The sunroof is definitely leaking and the headlining is knackered anyway. I read a thread on here about how to do it.
I ordered a new fuse box off Ebay for £30 with exactly the same part number so fingers crossed. I also took out the BCU and had a look but no obvious signs of damage.
Fuse box and BCU earth connections seem to be ok with the tester.
Thanks guys

Paul_Disco_II · Sep 22, 2020

Hi, The new fuse box came and was exactly the same as the old one. The PRWIND relay was missing but swapped it for the old one.
Fitted it and the problem is essentially still the same but the following are now working that weren't before: down hill mode, adjustable suspension, economy mode. The fuel pump is definitely coming on but I am not sure if this was working before or not.
So, warning lights on the dash are still the same. central locking not working. indicators not working. On the auto gear shifter, the lights indicating the different gears are on, but it doesn't show which gear its in (the small lights don't come on).
I thought is might be a dodgy connection on the wiring loom so I tested the large spade connectors and they seem ok.
I also put a sheet over the roof and wish i'd done it years ago!!
Is it BCU next or something else?
Many thanks.

Si Click · Sep 22, 2020

If the crossed B is still there then the ECU and BCU are still not communicating, and this probably accounts for the central locking at least. No experience myself of how to get them talking again, but there are a bunch of threads on here about how to do it and sierrafery is the font of all wisdom..

sierrafery · Sep 22, 2020

I'm affraid that the BCU is next as long as the IDM was ruled out

Paul_Disco_II · Sep 22, 2020

Thanks guys. That’s appreciated.
Is it better to get one with a key or doesn’t it make much difference?

sierrafery · Sep 22, 2020

The BCU needs complex programming with diagnostoic tool

ROY SIMPSON · Sep 23, 2020

Search callrova for advice and or replacement bcu .
Very knowledgeable and approachable.

Paul_Disco_II · Sep 23, 2020

Thanks for your help.
My D2 is Diesel and Auto. Does the new BCU have to come off a similar vehicle or doesn't it matter? I can't find exactly the same model on ebay at the moment.

sierrafery · Sep 23, 2020

The BCUs are fully programmable they are all the same but you need diagnostic tool to program it, no way around that

Paul_Disco_II · Sep 23, 2020

OK, thanks - that makes buying a new one a bit easier. Sorry, now that I am beginning to understand it all a bit more, I can see that you have answered these questions many times already. Thanks for your help.

Shippers · Sep 23, 2020

Speak to Rick at callrova as previously mentioned..

Paul_Disco_II · Sep 23, 2020

Thanks Guys - have contacted them and got a price for a test and a re-programme if its faulty.

ronsealdeath · Sep 24, 2020

Please do report back the outcome

Shippers · Sep 24, 2020

Paul_Disco_II said:
Thanks Guys - have contacted them and got a price for a test and a re-programme if its faulty.

Weve used them before for a customers car here in the Algarve..will use again if needed...

Disco 2 Electrical problems and dead. crossed B fault code

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